AMES, Iowa - The few questions from the moderator at a "Growing the Bioeconomy" conference at Iowa State University all had to do with the seemingly narrow issue of how to modernize agricultural production.
But when it was Joseph R. Biden Jr.'s turn to answer, he started talking about the shoddy state of American infrastructure, the efficiency of foreign ports such as Hong Kong, the trade gap with Asia, and the uncompetitiveness of US manufacturing.
The Delaware Democrat's apparent meander across the policy landscape Monday night was not an example of senatorial self-indulgence or his own legendary long-windedness, as much as of an increasingly distinctive approach to policy questions. Biden's complex answers often feature more movable parts than his Democratic rivals', usually reaching beyond typical issue categories such as economic, foreign, and trade policy.
Eventually he came to a novel point: One of the reasons American goods don't sell abroad is that having to reach foreign markets via outmoded domestic infrastructure can make them unduly expensive.
Most of Biden's presidential opponents have talked about the need to reinvest in infrastructure as a set of discrete policy choices: about spending money at home instead of in Iraq or the wisdom of earmarking a "bridge to nowhere" in Alaska when there's one in Minnesota that collapsed into the Mississippi River.
Biden's answer - which managed, in a few logical steps, to link crumbling highways to shuttered factories - did not turn on a supposed trade-off, but rather a Rube Goldberg-like chain of cause and effect.
He attempted something similar at last week's Democratic debate in Philadelphia. Biden faced a question on a resolution the Senate approved in September declaring part of the Iranian military to be a terrorist group - which he, like most of his opponents, opposed. But while his colleagues reached for hyperbole about the imminence of Bush-led armed conflict with Iran, Biden methodically started at the gas pump.
"It's not even about going to war," Biden said. "Let's look at what happened from the moment that vote took place: Oil prices went up to $90 a barrel." He explained his belief that "all this talk of war" was in part to blame for the high price of gas. "Even if not another single action is taken, actions have consequences," Biden warned.
Also in Ames, Biden tried to explain why the United States has not cut off toy imports from China despite lead and other health hazards found in them. "They own the mortgage on our house!" Biden exclaimed, moving from Thomas the Tank Engine to President Bush's 2001 tax cuts.
The cost of those tax cuts, Biden said, led to debt financed by Chinese purchases of US Treasury bills, which diminished American leverage to take trade actions against a growing economic power - as China did by banning American chicken imports after their safety was questioned.
"We don't seem to connect the dots very well," Biden lamented.
Sasha Issenberg can be reached at firstname.lastname@example.org.